Relations between language, non-verbal cognition, and conceptualization in non- or minimally verbal individuals with ASD across the lifespan

Abstract

Background & aims Individuals with non- or minimally verbal autism (nvASD) are primarily characterized by a severe speech production deficit, with speech limited to no or only a few words by school age. Significant unclarity remains over variability in language profiles across the lifespan, the nature of the language impairment seen, and (dis-) associations between linguistic and nonverbal cognitive measures. Methods To address these questions, we recruited both a school-age and an adult group with nvASD (total N = 49) and investigated relations between expressive and receptive language, and between these and nonverbal intelligence quotient (NVIQ) and sense-making capacities (the ComFor test). Results Results revealed limited variation across this sample in receptive language, which in turn predicted expressive language levels. Importantly, an upward trend in verbal mental age (VMA) across increasing chronological age was seen in the youngsters (only). A radical dissociation between NVIQ and both expressive and receptive language transpired as well, and a subset of individuals with normal NVIQ were comparable in terms of any other cognitive aspect. Sense-making reached symbolic levels in 62.2% of the sample and loaded on both verbal and nonverbal factors. Conclusions These patterns inform theories of nvASD by revealing an impairment that is not conceptualizable as one of expressive language only, sharply limits learning opportunities across the lifespan, and cannot be compensated for by nonverbal cognition. Implications These findings stress the need to seize developmental opportunities that may disappear when youngsters turn into adults, via therapies that specifically target language as a central cognitive system comprising both production and comprehension.

Grammar in ‘agrammatical’ aphasia: What’s intact?

“…To the same extent, aspects of aphasic speech said to be ‘agrammatic’ may be limited as a way of illuminating the neural basis of grammar and yield a distorted picture of the grammatical competence involved. To understand the neural basis of a true loss of such competence, other disease models would need to be considered, such as those 30% of children and adults with autism spectrum disorder (ASD) who never develop functional language to begin with, and who remain restricted in their linguistic repertoire to no or a handful of single words, with a uniform absence of grammar in production and comprehension [ 23 , 24 ]. On the other hand, the hypothesis of intactness is by no means uncontroversial and an equally prominent foundational view defines aphasia as language impairment dissociated from cognitive impairment [ 25 ].…”

The importance of deep speech phenotyping for neurodevelopmental and genetic disorders: a conceptual review

“…Many studies simply describe affected children as having “intellectual disability” or “speech delay”, even at times seeming to use these terms interchangeably (e.g., [ 19 , 83 ]). Others employ more specific measures of IQ (intelligence quotient), language, and speech to produce more detailed and accurate phenotypes (e.g., [ 82 ]). But because IQ, language, and speech are separable (though interacting) cognitive domains with distinct (though overlapping) neural substrates, in order to understand the full range of effects of specific genetic mutations, it is necessary to evaluate them all using psychometrically sound measures.…”

Language level predicts perceptual categorization of complex reversible events in children

“…(2019) , however, a potentially more powerful source of insight comes from school-age children with neurodevelopmental disorders, who do not develop language in either production or comprehension at all. This includes 30% of people on the autism spectrum ( Norrelgen et al., 2015 ; Slusna et al., 2021 ) – a population that, while neglected in research terms ( Jack and Pelphrey, 2017 ), is of considerable importance for raising fundamental questions about the neural basis of language and cognitive functioning under conditions of language absence ( Hinzen et al., 2019 ). Such children are unlikely to develop language later ( Slusna et al., 2021 ) and provide us with an alternative and arguably closer approximation of a ‘language-less’ mind than either neurotypical infants or verbally shadowing adults could do.…”

“…This includes 30% of people on the autism spectrum ( Norrelgen et al., 2015 ; Slusna et al., 2021 ) – a population that, while neglected in research terms ( Jack and Pelphrey, 2017 ), is of considerable importance for raising fundamental questions about the neural basis of language and cognitive functioning under conditions of language absence ( Hinzen et al., 2019 ). Such children are unlikely to develop language later ( Slusna et al., 2021 ) and provide us with an alternative and arguably closer approximation of a ‘language-less’ mind than either neurotypical infants or verbally shadowing adults could do. Absence or regression of language development is by no means confined to non- or minimally verbal autism, moreover, but found in various instantiations and degrees across numerous neurogenetic conditions including Phelan-McDermid, Angelman, Coffin-Siris, Landau-Kleffner, Rett, and Cri du Chat syndromes ( Hinzen et al., 2019 ).…”